In the conditions of permanent deficit and cost increase of the conventional hydrocarbon power sources, a special attention is paid to usage of so called alternative or renewable energy.
The power systems are known that are produced by plants working on ecologically clean renewable power sources (wind, sun, and etc.). Nevertheless, instability of energy flow in the source (change of wind strength, climatic and seasonal variations of light energy flow) creates obstacles in supplying the consumers with quality energy. To improve the power supply stability, the combined systems are developed where at the same time the energy of more than one sources is used, for example, wind and solar energy.
The Independent energy supply system for homes and industry is known (RU, A, 2249125), where the energy of wind, sun and Earth heat are utilized.
The Independent energy supply system for homes and industry contains a wind generator setup for electric power production connected to electric power consumers; electric energy storage battery connected with the wind generator setup and electric power consumers. To convert direct current of electric storage batteries into alternative current with parameters required for consumers the inverter is used that through the electric storage batteries are connected.
The system includes a plant for solar energy conversion into heat and a heat storage connected to the heat energy consumers. A heat pump driven by the wind generator setup is also used for providing the consumers with heat energy. To control the Independent energy supply system the automatic control system is used that connected through the heat and electric load sensors with actuating mechanisms. The plant for solar energy conversion into heat energy contains a unit of solar collectors coupled through the heat carrier, at least, with two heat exchangers, one of which is located in the heat storage, and other—in the heat-exchange apparatus connected through the heat carrier with the Earth heat storage system. The heat pump contains: compressor operating from the wind generator setup, at least, two external evaporators, one of which is built-up into the heat-exchange apparatus connected through the heat carrier with the Earth heat storage system, and other external evaporator is built-up in the sewage heat recovery unit, and at least two external condensers, one of which is built-up in the heat-exchange apparatus connected through the heat carrier with the heat power consumers.
The system described utilizes a renewable energy of wind, sun and Earth heat what makes possible to provide a sustained delivery of heat and electric power to the consumers even in the absence of/or at low energy flows from one of the power sources. The system is supposed to use not only the heat produced in the solar collectors, but also, so called, “waste” heat sources, for example, by means of sewage heat recovery.
The main disadvantage of the stated system is an insufficient efficiency due to energy losses during conversion procedure. The generators used in the wind generator setups are featuring of their output parameters direct dependency on a rotor speed (voltage, frequency), it means on wind speed as well. The storage battery carries a function of energy storage and voltage stabilizer.
In this system, electric current produced by the wind-powered generator is to be converted: at first the current is transformed to obtain the parameters needed for the storage battery charging. Then, a direct current from the storage battery is converted (inverted) to be supplied to consumers (as a rule an alternative current of 220 V 50 Hz is required). Energy losses, worsening the system parameters, take place at each step of transformation. When a heat and electric storage battery has been charged in full, heat and excessive energy are simply dissipated as generator's heat radiation.
Besides, the system described works effectively only within the specified designed range of winds. So, at strong winds the frequency of the generator current increases excessively, what results in losses increase at current conversion, and at gale-strength wind the wind generator setup may be damaged.